Instrument for geophysical exploration



Feb. 15, 1949. 1', zuSc INSTRUMENT FOR GEOPHYSICAL EXPLORATION Filed Dec. -15, 194.5

IN VEN TOR. 66 3 g a Patented Feb. 15, 1949 INSTRUMENT FOR GEOPHYSICAL EXPLORATION Theodore Zuschlag, We

signor to Hans T. F. tario, Canada st Englewood, N. J., as-

Lundberg, Toronto, On-

Application December 13, 1945, Serial No. 634,780

' 12 Claims.

1 This invention relates to an instrument for geophysical exploration of the magnetic type, and has for an object to provide a device which involves the principle of operation of a magnetic compass and which includes a plurality of needles arranged in difierent planes of operation.

Another object is to provide such a device in which the needles are spaced from each other so as to operate independently in substantially parallel planes, and in which either or both needles may be adjusted so as to operate at either side of the earths polar magnetic line.

Another object is to provide such a device in which both needles have an operative eiiect while readings are taken from a single needle.

Another object is to provide such a device which may be set for operation in various planes as, for instance, a horizontal plane and a vertical plane perpendicular thereto, in order to obtain data concerning the intensity of both vertical and horizontal components of the earth's magnetic field.

Another object is to provide such a device which substantially embodies a pair of compasses, one located above the other in spaced relation and arranged to be rotatably adjusted in opposite directions around an axis coinciding with the axes of their needles.

I sockets in the wall of a a base I, which is preferably circular, and a pair of uprights 2, 3 located at diametrically opposed positions on the base. The uprights are bored and threaded near their tops to receive thumbscrews 4, 5 which have reduced, unthreaded extremities 8,. I fitted to enter corresponding circular drum 8, whereby the drum is pivotally mounted between the uprights 2, 3. As the forming of the reduced ex- Another object is to provide a device as described in the preceding paragraph in which the said pair of compasses may be rotatably adjusted in the same direction about an axis perpendicular to the axes of their needles. 1

Another object is to provide .such a device which includes a pair of needles spaced from each other and operative in substantially parallel planes, together with means for locking either or both needles to prevent either or both from being influenced by magnetic force and means for positively setting either or both needles in desired positions. A further object consists in providing certain improvements in the form, construction, and arrangement of the several parts whereby .the above named and other objects may be effectively attained.

A practical embodiment of the invention is represented in the accompanying drawing, in which Fig. 1 represents a top plan view;

Fig. 2 represents a vertical central section, partly in elevation; and

Fig. 3 represents a broken, detail elevation of an exterior portion of the upper compass.

The instrument includes a framework having tremities 6, I, provides shoulders on the thumbscrews 4, 5 adjacent the wall of the drum 8, the latter may be secured in various rotative angular positions by tightening the said thumbscrews.

An upper circular casing'9 is located at the upper part of the drum 8 and has a spider composed of a ring l0, and three arms M, ii, ii, fixed to its upper edge by screws l2, l2, i2, i2. A ring it is formed integrally with the lower edge of the casing 9 spider arms, two of which are shown and marked id, it, that are similar to and in vertical alinement with arms M, H, H. The casing 8 is held against movement upwardly of the drum 8 by the outwardly protruding edge of the ring l3 which is overlapped by a circular clamp it that is6 flxgd liio the top of the drum 8 by screws i8,

A lower circular casing IT has a solid bottom 18 formed integrally therewith, while a spider consisting of a ring l9, and three arms, two of which are shown and marked 20, 28, is fastened to its upper edge by four screws, two of which are shown and marked 2!, 2|. The casing I1 is held in position against downward movement out of the drum 8 by the outwardly extending edge of the ring H which is underlapped by an annular clamp 22 that is fixed to the bottom of the drum by screws, of which two are shown and marked 23, 23.

The'said upper and lower casings are kept in spaced relationship by a plurality (four being shown) of rollers 24, 25, 26, 21, which rollers preferably have at least their peripheries composed of some suitable material that is slightly yielding and has frictional characteristics such, for instance, as fairly hard rubber: it being understood that the strength and consistency of the said rollers must be sufflcient to maintain their shape and hold the said upper and lower casings in position with substantial rigidity.

All four rollers 28, 25, 26, 21 have their hubs pinned or otherwise suitably secured to stud shafts 28, 29, 30, 3! which are mounted for tree rotation in the drum 8; and shafts 28 and 38 of rollers 24 and 28 have thumbwheels 82, 82

and is provided with three pinned thereto. As a result of this construction, the manual turning of either wheel 32 or at will rotate the roller with which it is connected and thereby act upon the bottom of ring it of the upper casing and the top of ring IQ of the lower casing so as to rotatlvely adjust the said casings in opposite directions. Of course, simultaneous manual rotation of both wheels 32, 33, in opposite directions, will accomplish the same result and, during these adjustments, the rollers 25 and 21 serve as idle supports and spacing elements for the said upper and lower casings 9 and ii. Shafts 2t and 3i may be provided with enlarged outer ends to prevent inward movement thereof.

A magnetic compass needle 86 has its hub provided with trunnions 35, g with bearings 31, 88 formed at the junction of spider arms H, H, H, and spider arms M, l6, l4 respectively, the arrangement being such that the needle 36 may turn under the influence of magnetic force as in ordinary compasses. A latch 39 is mounted in a, hole formed in the wall of upper casing 9 and has an inner bifurcated end 40 which straddles trunnion 36, and its outer end provided with a knob M for manipulation. It will be observed that the said latch has a hump 42 adjacent its bifurcated end whereby inward manual sliding of the said latch will lift the needle 34 by a cam-like action and jam its hub against bearing 37 with the result of locking the needle to prevent deflection by magnetic force.

Another magnetic needle 43 is located in the lower casing Ill and has its hub provided with trunnions 3E, 45 for cooperation with bearings 46, fill, located at the junction of spider arms 20, 20, 2B and at the center of bottom it, respectively. A latch 68 similar in form to latch 39 is mounted in a hole formed in the wall of lower casing ill and is adapted to lock the needle 43 against magnetic deflection in the same way as has been described. in connection with latch 8t and needle 34.

Water levels 69 and Ell are mounted perpendicular to each other on the top of base i of the framework, and a thermometer 5! is also fixed on the top of said base.

A circular support 52 underlies base i and is pierced with a central bore to receive a pivot stem 63 which is formed integrally with the base I and projects downwardly therefrom, the lower portion 54 of said pivot stem being reduced in size and mounted in the head 55 of a tripod of standard or other suitable form which has the usual three legs, two of which are indicated generally by 56, 5?, pivoted at 58, 58. The shoulder formed by the reduction in size of the portion 54 of the stem serves to support the framework l, 2, 3, and parts carried thereby, on the head 55, and a wing nut 59 is threaded on the extremity of the stem 53 to secure the parts thereabove to the tripod.

A pair of shafts 60, iii are horizontally mounted in diametrically opposed bores formed in the support 52, and their inner ends project into an annular recess 82 formed in the said support.

'To the inner ends of shafts '50, 6! are pinned tapered rollers 64, 65, which may be composed of fairly hard rubber or other appropriate material having slightly yielding and frictional characteristics as indicated at 63, which rollers are fitted for contact with a correspondingly tapered ring 66 that is secured to, or formed integrally with, the underside .of base I. The outer ends of shafts $0, 6! have thumbwheels 61, B8

It will 36 fitted to cooperate pinned thereto, whereby manual turning of either I of said thumbwheels, or simultaneous turning of both of said wheels in opposite directions, will adjust the framework l, 2, 3, and parts carried thereby in a rotary direction on the support 52.

also be observed that shaft BI is somewhat longer than shaft 60 so that it protrudes laterally from the edge of support 52. as a result of which the operator can manually push the shaft 8i inwardly and cause its roller 65 to jam on the ring 68 for locking the framework i, Z, t in any selected position of adjustment.

A ring 69 is fixed on the top of ring it and bears on its upper face a usual compass scale having two zero markings diametrically opposed to each other and two ninety degree markings diametri- 'cally opposed to each other at right angles to the diameter on which the zeros are located, whereby the deflection of needle 34 may be read. A similar scale 70 is formed on the' iower portion of the outer circumference of easing 9 and an index arrow or the like H is located at a suitable point on the upper surface of the annular clamp l5 for cooperation with the scale 10. A third scale 12 drum 8. This may consist of any well known or approved form of device, such, for instance, as a pair of notched elements M, It, hinged, as indicated at 15, at diametrically opposed points on 40 Assuming the needles 34 the outside surface of the drum. The said elements may be permitted to hang downwardly when not in use and be swung upwardly, as shown in Fig. 2, for operation.

and 43 tq have approximately the same magnetic or pole strength. they will take a symmetrical position or angle with respect to and on opposite sides of the earths magnetic north-south line, if they are released and permitted to be subjected to magnetic defiection. The value or degree of the spread angle between the two needles is a function or result of the intensity of the earths magnetic field, the distance or spacing between the two needles, and their respectivepole or magnetic strength. Thus, if the spacing or distance between the needles and their pole or magnetic strength be maintained constant. the spread angle of the needles will be a measure of the intensity of the component of the earths magnetic field which is acting upon the needles. If the needles can be forced to cross from one side to the other of the earths north-south magnetic line, they will again take symmetrical positions or angles with respect to the said line, and the spread angle of the needles thus established will be a counterpart of the previously established spread angle. In view of these facts, it is evident that the value or degree of the spread angles can be determined or observed by noting the degree of angularity between the two positions taken by the upper compass needle 84 when establishing the two spread angles to which reference has been made, so that it is not necessary for the operator to observe or read the angularity of the lower needle 43, nor is it necessary to provide any scale for cooperation with the said needle.

When using this instrument in geophysical prospecting, the operator selects the desired point of observation and either determines or informs himself, in any well known or approved manner, of the approximate direction of the earth's magnetic field at the said point. The tripod supporting the instrument is thereupon set at the selected point and the instrument is leveled by observation of'the water levels 49 and 50. while the temperature may also be noted from the thermometer II. In order to better.the observation of these 7 instruments. it is convenient to have the drum 3 and parts carried thereby removed from the framework I. 2, 3 at the time.

Following observation of the levels and thermometer, the drum and'associated parts are set in operative position in the framework I, 2, 3, it being'understood that the removal and resetting of the said parts is accompanied by manipulation of the thumbscrews 4, 3. The operator then orients the instrument within the direction of the earth's magnetic field by use of the sight 14 and rotary adjustment of the framework I. 2, 3 by either or bother the thumbwheels 31. 63. The thumbwheel 88 is then pressed inwardly-to jam the roller 85 on the ring 66 and lock the instrument in the said directional adjustment.

Both needles 34 and 43 are locked against deiiection by use of the latches 33 and 43, and one or both thumbwheels 32, 33 is or are rotated until the upper casing 9 has been turned to bring the index arrow Ii opposite zero on scale Ill. The latches 33 and 43 are then released so as to permit magnetic deflection of the needles, and the angularity or deflection of needle 34 is read on scale 33 and recorded. The latches 39 and 48 are again operated to lock both needles and one or both thumbwheels 32, 33 is or are again rotated to turn the upper casing 9 and parts carried thereby until the'index arrow Ii points to a degree on scale 10 which is twice the degree of the angularity of needle 34 previously noted and recorded. This turning of the upper casing 9 and associated parts of course correspondingly turns the lower casing i1 and its associated parts an equal distance in the opposite direction, whereby the relative positions of the needles 34 and 43 are reversed. With the instrument in this adjustment, the latches 39 and 48 are manipulated to release the two needles and the angularity taken by needle 34 is noted on scale 69 and recorded.

It, now, the angular position first taken by needle 34 is denoted by a; the position to which the upper casing 3 is thereafter turned is denoted by 20.; and the second angular position taken by the needle 34 is denoted by b; the value or degree of the angle between the true northsouth line and the zero line ofthe instrument (which may be called the declination D) together with the horizontal intensity of the earth's magnetic field at the point under investigation (which may be called intensity H) can be computed with the following formulae:

and

H 03 cos g represents. of course,-the cosine of one-half of the spread angle a+b.

The horizontal intensity of the earth's magnetic field having thus been determined, the operator may proceed to determine the vertical intensity of the said field in a similar manner. To accomplish this, the orientation of the instrument is readjusted by pulling thumbwheel 38 outwardly to release the lock of its roller 85 against the ring 88, and then rotating one or both of the thumbwheels 81, 83 until the index arrow 13 on support 32 points to a degree on scale 12 which corresponds to the angle of declination D previously determined. One or both of the thumbscrews 4, 5 is or are released and the drum 8 and parts carried thereby are turned in a vertical plane a distance of ninety degrees and locked in said position by tightening the said thumbscrews; both needles being locked during this operation. By manipulation of one or both thumbwheels 32, 33, the casing 9 is turned until the index arrow Ii points to zero on scale 10.

The needles are now released and the deflection angle of needle 34, which may be called angle c, is read on the scale 39 and recorded. Both needles are again locked, and the casing 9 is turned until the index arrow Ii points to a degree on scale Hi which is twice that of the angle c just recorded and may be called angle 20; which last named step, of course, turns casing ii an equivalent distance in the opposite direction. Both needles are again released and the deflection angle taken by needle 34, which may be called angle d, is noted on scale 83 and recorded. The vertical intensity of the earths magnetic field at this point, which may be called intensity V, can now ;be calculated by use of the formula V= Cw cos $621) the pole or magnetic strength of the needles and their horizontal distance or displacement from each other, while plored and the'results of the measurementsor determinations can be plotted and interpreted as to their geophysical meaning by those skilled in this art in any well known and approved way.

It may be mentioned that the sensitivity of the instrument can be changed by using needles of difierent relative magnetic or pole strength, or by changing the spacing or distance between the needles, or by both changes. The change in the spacing of the needles from each other can be accomplished by using drums 8 of different height or by substituting complete units corresponding to the drum 8 and parts carried thereby, in which units the needles have different spacings. Generally speaking, the greater the spacing of the needles, the greater the sensitivity of the instrument, while the greater the magnetic or pole strength of the needle, the greater its angle of deflection or declination with respect to the earth's north-south magnetic line and the earth's magnetic field at the point under investigation. Changes in sensitivity may be desirable with respect to operations at different latitudes and under difierent conditions of strength of the earths magnetic field, as well as in other cases. It lis possible also to'employ compensating magnets, preferably symmetrically located with respect to the two needles, for the purpose of, in eflect, eliminating an arbitrary part of the strength of the earth's magnetic field and thereby making more apparent variations in the field reflected by the handling of the instrument and the computations hereinabove detailed.

The instrument forming the subject matter of this invention is not only applicable for geophysical exploration on the ground by being consecutively located at different points, but it is also highly efficient and desirable in connection with exploration from moving supports such, for instance, as air and water craft; an airplane of the helicopter type being especially desirable because of its adaptability to either slow or rapid horizontal flight, to vertical movement, to the.

holding of fixed positions, as well as other characteristics inherent in such a plane.

It will be understood that various changes may be resorted to in the form, construction, arrangement and material of the apparatus, without departing from the spirit and scope of this invention; andhence I do not intend to be limited to details herein shown and described eX- cept as they may beset forth in the claims or required by disclosures of the prior art.

What I claim is:

1. An instrument for geophysical prospecting comprising, a pair of magnetic compass needles of substantially the same pole strength, mountings for supporting the needles to operate in 'spaced planes with their axes of rotation in substantial alignment, means for simultaneous rotary adjustment of the mountings in opposite directions, and means for simultaneous rotary adjustment of the needles in the same direction in a plane at right angles to the planes of the firstnamed adjustment. 4

2. An'instrument for geophysical prospecting comprising, a pair of magnetic compass needles of substantially the same pole strength, mountings for supporting the needles to operate in spaced planes with their axes of rotation in substantial alignment, means for rotary adjustment of the mountings in opposite directions, means for rotary adjustment of the needles in a plane at right angles to the planes of the first named adjustment, and means for rotary adjustment of the mountings in the same direction in the same plane as the first named'adjustment.

3. An instrument for geophysical prospecting comprising, a framework mounted for rotary adjustment in one plane, a unit mounted in the an angle to the first named plane, a pair of mem- ,bers mounted in the unit for rotary adjustment in planes parallel to each other, and magnetic compass needles mounted in said members with their axes of rotation in substantial alignment.

4. An instrument for geophysical prospecting comprising, a framework mounted for rotary ad- -ju stment in one plane, a unit mounted in the framework for rotary adjustment in a plane at right angles to the first named plane, a pair of members mounted in the unit for rotary adjustment in planes parallel to each other, and magnetic compass needles mounted in said members with their axes of rotation in substantial alignment. i

5. An instrument for geophysical prospectingcomprising, a framework mounted forrotary adframework for rotary adjustment in a plane at justment in one plane, a unit mounted in the framework for rotary adjustment in a plane at rightangles to the first named plane, a pair of members mounted in the ,imit for rotary adjustment in opposite directions in planes parallel to each other, and magnetic compass needles mounted in said members with; hair axes of rotation in substantial align entt 6. An instrument for geophysical prospecting comprising, a framework mounted for rotary adjustment in one plane, a unit mounted in the framework for rotary adjustment in a plane at right angles to the first named plane, a pair of members mounted in the unit for rotary adjust ment in planes parallel to each other, magnetic compass needles mounted in said members with their axes of rotation in substantial alignment, and a rotatable device also mounted in the unit and contacting both said members for imparting thereto the said rotary adjustment.

7. An instrument for geophysical prospecting comprising, a framework mounted for rotary adjustment in one plane, manually operable means for accomplishing said rotary adjustment, a drum mounted in the framework for rotary adjustment in a plane at right angles to the plane of adjustment of the framework, a pair of casings movably mounted in the drum, a rotatable device located in the drum between and in contact with the casings, means for rotating said device for rotary adjustment of the casings in opposite directions in planes parallel to each other, and. magnetic compass needles mounted in said casings with their axes of rotation in substantial alignment.

8. An instrument for geophysical prospecting comprising, a framework mounted for rotary adjustment in one plane, manually operable means for accomplishing said rotary adjustment, a drum mounted in the framework for rotary adjustment in a plane at right angles to the plane of adjustment of the framework, a pair of casings movably -mounted in the drum, a rotatable device located in the drum between and in contact with the easings, means for rotating said device for rotary adjustment of the casings in opposite directions in planes parallel to each other, magnetic compass needles mounted in said casings with their axes of rotation in substantial alignment, and means for locking the framework, the drum, and the needles against movement.

9. An instrument for geophysical prospecting comprising, a framework mounted for rotary adjustment, a drum mounted in the framework for rotary adjustment in a plane at right angles to the plane of adjustment of the framework, a pair of casings movably mounted in the drum, 8, set of rollers located in the drum between and in contact with the casings, means for rotatingat least one of said rollers for rotary adjustment of the casings in opposite directions, and magnetic compass needles mounted in said-casings with their axes of rotation in substantial alignment.

10. An instrument for geophysical prospecting comprising, a framework mounted for rotary adjustment, a drum mounted in the framework for .rotary adjustment in a plane at right angles to the plane of adjustment of the framework, a pair of casings movably mounted in the drum, a set of rollers located in the drum between and in contact with the casings, means for rotating at least one of said rollers for rotary adjustment of the casings in opposite directions, magnetic compass needles mounted in said casings with their axes of rotation in substantial alignment, and

means for orienting and leveling the framework.

11. An instrument for geophysical prospecting comprising, a framework mounted for rotary adjustment, a drum mounted in the framework for rotary adjustment in a. plane at right angles to the plane of adjustment pair of casings movably mounted in the drum, a set of rollers located in the drum between and in or the framework, a' a contact with the casings, means for rotating at I least one of said rollers for rotary adjustment of the casings in opposite directions, magnetic compass needles mounted in saidv casings with their axes of rotation in substantial alignment, and means for locking either needle against movement under magnetic influences.

12. An instrument !or geophysical prospecting comprising, a framework mounted for rotary adjustment, a drum mounted in the framework for rotary adjustment in a plane at right angles to the plane of adjustment oi the framework, a pair of casings movably mounted in the drum, a set of rollers located in the drum between and in contact with the casin s. means for rotating at the casings in opposite directions, magnetic compass needles mounted in said casings with their axes of rotation in substantial alignment, means for locking either needle against movement under magnetic influences, and a degree scale associated with one or the needles.

1 THEODORE ZUSCHLAG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS least one of said rollers for rotary adjustment of Germany Feb. 17, 1927 

